This proposal is concerned with the development of the relatively new technique of circularly polarized luminescence (CPL) spectroscopy as a useful probe for monitoring conformational changes in biochemical systems. CPL is the emission analogue of circular dichroism (CD), and involves the measurement of the small net circular polarization in the luminescence of optically active molecules. Although CPL spectroscopy has developed into a useful spectroscopic probe in a fairly wide variety of chemical systems, its usefulness in obtaining specific information concerning the structure of biomolecular systems has been limited, even though the number of luminescent biomolecular systems is quite large. This has been primarily due to the fact that it has often been necessary to work at fairly high concentrations of the luminescent material, and often the excitation process itself (often in the UV) results in photochemical changes. In this work we will be concentrating on the use of luminescent lanthanide(III)ions which we will excite with visible laser excitation. Our experimental apparatus allow us to work at very low concentrations, and the use of wavelength-selective and polarization selective excitation will allow addition high discrimination between luminescent sites. Primary emphases in the work proposed here will be place in the following two areas; CPL as a specific probe of conformational changes in calcium binding proteins, and the potential use of CPL spectroscopy measured through a microscope objective. The ultimate goal of this work is to be able to suggest specific application of CPL to clinical or diagnostic studies.